JP3422262B2 - Sample cooling device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an analyzer for automatically analyzing, for example, a liquid sample, and more particularly to a sample cooling device for cooling a liquid sample before analysis in a liquid chromatograph. About. 2. Description of the Related Art In an automatic analysis in a liquid chromatograph, a sample container in which a small amount of a sample has been sealed is previously mounted on a rack, and this rack is set in an automatic sample injecting apparatus. This is performed by sequentially sucking samples from the upper sample container according to a predetermined program and injecting the samples into a liquid chromatograph. Samples on racks that are waiting for analysis are often placed at room temperature, but some samples may need to be kept cool to prevent degradation. In such a case, a device used for cooling the sample is a sample cooling device. There are two conventional sample cooling devices, a direct cooling type and an air cooling type. In the direct cooling type, the rack is made of metal with good heat conductivity, and a cooler (Peltier element, etc.) is provided at the bottom of the rack.
And the temperature of the sample is adjusted mainly by heat conduction through the solid. In the air-cooled type, a main part of an automatic sample injecting apparatus including a rack is surrounded by a heat insulating case, the air inside is cooled, and the temperature of the sample is adjusted via the air. Next, the two conventional methods will be described in more detail with reference to the drawings. FIG. 2 shows an example of a conventional direct cooling type sample cooling apparatus. The analyst first puts the liquid sample 4 into a sample container (usually a small glass bottle) 2 and seals its mouth with a septum 3 (strictly 3 is composed of a septum and a cap, but is abbreviated as a septum hereinafter). This is mounted on the rack 1 removed from the automatic sample injector 7 and taken out. The rack 1 is made of aluminum and is provided with about 100 holes 5 into which the sample containers 2 are inserted. Heat (including cold) is transmitted to the sample container 2 through the bottom of the hole 5 and the inner wall of the hole. The rack 1 on which the sample has been loaded is set on a metal block 23 in the apparatus. Metal block 2
Reference numeral 3 denotes a heat transfer member which is cooled by a Peltier element 21 attached to its lower surface, and whose surface is in close contact with the bottom of the rack 1 to maintain good heat conduction. In this case, the rack 1 also functions as a heat transfer member that transmits heat to the sample container 2. The temperature control circuit 25 compares a control target value (hereinafter, referred to as a predetermined temperature) set by the temperature setting unit 26 with a signal from a temperature sensor 24 embedded in the metal block 23 and detecting the temperature. By supplying a current (cooling energy) to the Peltier element 21 so as to make the difference close to zero, the temperature of the metal block 23 is controlled, and finally the metal block 2 which is a heat transfer member is controlled.
The liquid sample 4, which is thermally integrated with the rack 3 and the rack 1, is maintained at a predetermined temperature. On the back surface (radiation surface) of the Peltier element 21,
A radiating fin 22 is attached to the inside of the ventilation duct 27 so that heat absorbed from the metal block 23 is radiated by the fan 28 through the fin 22. With such a configuration, the rack 1, the sample container 2 mounted thereon, and the sample liquid 4 therein are maintained at a predetermined low temperature. The rack 1 is covered with a heat-insulating cover 6 to keep cool, but the head of the sample container 2 (septum 3 and its surroundings) is exposed from the cover 6 to enable the sampling needle 13 to take out the sample. ing. The sampling needle 13 can be moved up and down, left and right, and up and down by a mechanism (not shown). According to a program, the sampling needle 13 penetrates the septum 3 to suck up the liquid sample 4 from the sample container 2 and moves to the sample inlet 12 of the liquid chromatograph. Automatic analysis is then performed by injecting a sample into this. Liquid chromatographic analysis is 1
Since a sufficient number of times are required, the sample on the rack 1 is long and waits for analysis for several tens of hours. During this time, the sample is prevented from being deteriorated by being kept at a low temperature. FIG. 3 shows an example of a conventional air-cooled sample cooling device. A main part of the automatic sample injector 7 including the rack 1 on which the sample container 2 is mounted is surrounded by a heat insulating wall 11 to form a thermostatic bath 10. Although not particularly shown, a part of the heat insulating wall 11 serves as a door to enable the rack 1 to be taken in and out. In this case, unlike the case of the direct cooling type, the rack 1 is made of a thin metal plate or the like in a shape having many voids in order to increase air permeability and reduce heat capacity in consideration of the fact that air is a heat medium. Therefore, the space around the sample container 2 mounted on the rack 1 and the space in the thermostat 10 are thermally equivalent. According to the present invention, in order to solve the above-mentioned problems, a cooling apparatus for accommodating a sample container containing a sample in a thermostat and cooling it to a room temperature or lower is provided. a first temperature adjusting mechanism comprising a condenser and temperature controller for adjusting cooling the internal space to a predetermined temperature, a cooler for adjusting cooling the sample container via the heat transfer member A second temperature control mechanism comprising a temperature controller;
By operating the first temperature control mechanism, the inside of the
After the temperature was adjusted to a constant temperature, the operation of the second temperature adjusting mechanism was started and controlled. Since water in the air condenses on the surface of the cooled metal block 33 to form dew, a drain receiver 14 and a drain tube 15 connected to the drain receiver and connected to the outside of the tank are provided to discharge the dew water. Is provided. By such means, the air in the tank is dehumidified, and the absolute humidity decreases as the temperature decreases. With such a configuration, the sample container 2 on the rack is wrapped in air that has been cooled and dehumidified, cooled from all around, and kept at a predetermined low temperature. [0011] Among the above two conventional types of sample cooling devices, the direct cooling type has a high heat transfer efficiency and can be cooled to a predetermined temperature in a short time. The moisture in the atmosphere condenses on the surface of the sample container or rack 1
This produces what is called dew condensation. Condensation water adheres to the tip of the sampling needle 13 and mixes with the sample during sampling, which may reduce the accuracy of the analysis. In addition, when the sample container 2 or the rack 1 is handled, water may drips around the sample container 2 or the rack 1. It is inconvenient to handle such as soiling. On the other hand, in the air-cooled type, since there is no fear of dew condensation on the surface of the sample container 2 or the rack 1 because the air is cooled by dehumidified air, the entire thermostat having a large heat capacity is heated using air having a small heat capacity as a heat medium. The cooling rate is slow due to cooling.
Even in the air-cooled type, if a powerful cooler is used and a fan is installed in the tank to forcibly circulate the air in the tank, the speed can be considerably increased, but it is not economical because energy consumption increases more than the effect . As described above, the conventional cooling device has advantages and disadvantages, and it is difficult to obtain a cooling device capable of rapid cooling without dew condensation and having high energy efficiency. The present invention has been made in view of such circumstances,
It is an object of the present invention to provide a sample cooling device using a new method in which the advantages of the conventional two types of sample cooling devices are combined and the disadvantages are improved. According to the present invention, in order to solve the above-mentioned problems, the present invention provides a sample cooling apparatus for accommodating a sample container containing a sample in a thermostat and cooling it to room temperature or lower. A first temperature control mechanism including a cooler and a temperature controller for adjusting the internal space of the sample container to a predetermined temperature, and a cooler and a temperature for adjusting the temperature of the sample container via a heat transfer member. A second temperature control mechanism comprising a controller, and the operation of the second temperature control mechanism is performed based on temperature information or humidity information in the bath, or elapsed time from the start of operation of the first temperature control mechanism. It was controlled based on. In other words, according to the present invention, a rack provided with a direct cooling type temperature control mechanism is housed in a constant temperature bath of an air-cooled sample cooling device, and is directly cooled in a dehumidified environment to reduce condensation. This allows rapid cooling without occurrence, and controls the operation of the direct cooling type temperature control mechanism until the inside of the tank is sufficiently dehumidified. FIG. 1 shows an embodiment of the present invention. In this figure, the same parts as those in FIG. 2 or FIG. In FIG. 1, a first temperature control mechanism 30 including a Peltier element 31, a radiation fin 32, a metal block 33, a temperature sensor 34, a temperature control circuit 35, a temperature setting section 36, a fan 38 and the like is shown in FIG. It cools air in the thermostatic bath 10 surrounded by the heat insulating wall 11. Further, the second temperature control mechanism 20 including the Peltier element 21, the radiation fin 22, the metal block 23, the temperature sensor 24, the temperature control circuit 25, the temperature setting unit 26, the fan 28, etc. The sample container 2 mounted on the rack 1 is cooled via a rack 1 which is a heat transfer member. The apparatus of this embodiment operates as follows.
First, the first temperature control mechanism 30 is operated first. When the surface temperature of the metal block 33 (cooling fin) decreases and the nearby air is cooled and reaches a dew point, dew forms on the surface of the fin. When the air in the thermostat 10 diffuses or comes into contact with the fins one after another due to natural convection, the temperature is lowered and the moisture is gradually removed, so that the absolute humidity is lowered. Since the air has a small heat capacity, it is cooled to a predetermined temperature in a short time, but the temperature of the rack 1 and the temperature of the sample container 2 thereon are delayed. When the temperature of the air in the bath approaches a predetermined temperature, the second temperature control mechanism 20 is started to operate by the control device 29 based on the signal from the temperature sensor 16, and the rack 1 and the sample container 2 are cooled. start. At this time, since the absolute humidity of the atmosphere has already been reduced, no condensation occurs even if it is rapidly cooled. Since it is directly cooled, the cooling rate is fast and reaches a predetermined temperature rapidly. The temperature settings of the two temperature control mechanisms 20 and 30 are basically the same, and the air inside the thermostat 10 and the rack 1 eventually have the same temperature. Therefore, unlike the conventional direct cooling type, it is not necessary to cover the periphery of the rack 1 with a heat insulating cover, but a cover may be used. The above is the case where the control device 29 is operated based on the temperature information in the tank. As a more direct means, a humidity sensor for detecting the absolute humidity is replaced with the temperature sensor 1.
The controller 29 may be used instead of 6 so that the controller 29 is operated by a signal from the humidity sensor, and after confirming that the absolute humidity in the tank has dropped, the controller 29 can be configured. Further, if a certain period of time has elapsed since the first temperature control mechanism 30 started to operate, the temperature and the absolute humidity in the tank will decrease.
9 may be replaced by a timer, and the operation of the second temperature control mechanism 20 may be started after a certain time from the start of operation of the first temperature control mechanism 30. Further, a method using a dew condensation sensor, which is one of sensors for obtaining humidity information, can be considered. The dew condensation sensor is stuck on the surface of the rack 1 or the metal block 23, and when the dew is detected, the operation of the second temperature control mechanism is stopped. With such control, the rack 1 can be cooled even while dehumidifying, so that the temperature of the rack 1 can be decreased substantially following the dew point temperature, and the rack 1 can be cooled to a predetermined temperature in the shortest time without dew condensation. Can be. Although the above description has been made by taking a liquid chromatograph as an example, the present invention can be applied to other analyzers for analyzing a liquid sample, and further, a sample pretreatment device, a reaction device, or a sample. It can be widely applied to devices other than analyzers such as storage devices. Further, a Peltier element has been exemplified as the cooler. In addition, a cooler utilizing vaporization heat absorption accompanying adiabatic expansion, a cooling method of circulating a refrigerant liquid cooled outside the system through a pipe, or the like can also be used. The temperature control mechanism including these coolers is not limited to the illustrated one, and various modifications can be considered. The requirements are as follows. The first temperature adjustment mechanism is a mechanism that cools the space in the tank with a cooler and adjusts the temperature so as to maintain a predetermined temperature, and the second temperature adjustment mechanism is that the sample is cooled from the cooler via a heat transfer member. This is a mechanism for cooling the container or the sample in it and adjusting the temperature. As described above in detail, the present invention is applied to a dehumidified environment in which a rack provided with a direct cooling type temperature control mechanism is accommodated in a thermostat of an air-cooled sample cooling device. Direct cooling is performed, and the operation of the direct cooling type temperature control mechanism is controlled until the inside of the tank is sufficiently dehumidified.Therefore, rapid cooling without dew condensation occurs. In addition, energy consumption is not particularly increased during the steady operation as compared with the conventional method.

[Brief description of the drawings] FIG. 1 is a diagram showing one embodiment of the present invention. FIG. 2 is a diagram illustrating an example of a conventional sample cooling device. FIG. 3 is a diagram showing another example of a conventional sample cooling device. [Explanation of symbols] 1 ... Rack 2. Sample container 3. Septum 4: Liquid sample 10 ... constant temperature bath 11 ... thermal insulation wall 12 ... Sample inlet 13 ... Sampling needle 16. Temperature (humidity) sensor 20, 30 ... temperature control mechanism 21, 31 ... Peltier element 22, 32 ... radiation fins 23, 33 ... metal block 24, 34… Temperature sensor 25, 35 ... temperature control circuit 26, 36 ... temperature setting part 27, 37… Ventilation duct 28, 38… Fan 29 ... Control device

Continuation of the front page (56) References JP-A-10-78387 (JP, A) JP-A-6-323714 (JP, A) JP-A-9-298225 (JP, A) JP-A-8-327615 (JP) JP-A-10-192719 (JP, A) JP-A-6-16863 (JP, U) JP-B-46-12350 (JP, B1) (58) Fields investigated (Int. Cl. ⁷ , DB G01N 1/00-1/44 G01N 30/00-30/96 B01L 7/00 F25B 21/02 F25D 31/00 EUROPAT (QUESTEL) JICST file (JOIS)

Claims (1)

(57) [Claim 1] In a cooling device for accommodating a sample container containing a sample in a thermostat and cooling it to room temperature or lower, the internal space of the thermostat is cooled to a predetermined temperature and adjusted. A first temperature control mechanism comprising a cooler and a temperature controller for cooling the sample container via a heat transfer member, and a second temperature control device comprising a temperature controller. The temperature control mechanism and the front
The inside of the constant temperature chamber is determined by the operation of the first temperature control mechanism.
A sample cooling device comprising a control device that starts and controls the operation of the second temperature control mechanism after the temperature is controlled.